Time-delay switch



April 9 1946. B. JONES TIME DELAY SWITCH Filed Jan. 5, 1945 QvwQ/YM Jon-es.

r m m 0 a W 7 J w 1 7/ 4 M w W Patented Apr. 9, 1946 UNITED STATES PATENT OFFICE TIME-DELAY swrron David B. Jones, Mount Olive, N. C. Application January 5, 1945, Serial No. 571,394

3 Claims. (01. 200-33) This invention relates to time delay switches, and more particularly to a time delay switch of the controlled vacuum type.

A main object of this invention is to provide a time delay switch adapted to open or close a pair of electrical contacts after a predetermined time interval.

A further object of this invention is to provide an improved controlled vacuum structure for introducing a predetermined time delay in the operation of an electrical switch to control the energization or de-energization of electrical equipment, lighting circuits, and the like.

Further objects of the invention will appear from the following description and claims, and from the accompanying drawing, wherein:

Figure 1 is a vertical cross-sectional view of a time delay switch structure in accordance with this invention.

Figure 2 is a cross-sectional view taken on line 2 -2 of Figure 1.

Figure 3 is a detail view showing the structure of the timing valve used in the device of Figure 1.

Figure 4 is a detail viewof an indicator scale structure for the timing valve.

Time delay switches have a multitude of useful applications. Examples of such useful applications are the setting of a time switch for operating household equipment such as washing machines for a predetermined length of time, or the setting of a time switch for opening a household lighting circuit to turn all the lights a predetermined time after the switch has been actuated. To illustrate the present invention, a structure is now described for maintaining an electrical circuit closed for a predetermined time period after the switch-operating knob'has been released to open position.

Referring to the drawing, i designates a main housing wallforming a support member upon which a switch housing member 2 is supported. Housing member 2 is provided with electric terminals 3 and 4 extending through the switch housing walls and provided with appropriate in sulating bushings which also serve to provide an air-tight seal for the respective terminals 3 and 4 in the walls of housing member 2. At the base of housing member 2 a pair of internal ribs 5 and 6 are provided and a strip of stiff insulation material 1 is forced into the base of housing member 2 into abutment with ribs 5 and 5.

An external flange 8 is formed on the base of housing member 2 over which is tightly fitted the bead of a bellows member 9. Bellows member 9 carries an axial rod l0 formed with a bottom head portion 1 I molded into the bottom of said bellows member 9. Rod l0 extends upwardly and fits loosely through insulation strip 1, a collar l2 being secured on said rod In to normally bear on the top surface of strip 1 and limit downward movement of rod i0 while allowing upward movement thereof.

A pair of contact members i3 and I4, respectively, connected to terminals 3 and 4, are mounted on strip 1 and are provided with contact elements l5 and I6, at the lower surface of strip 1. A metal disc I! adapted to connect contact elements I5 and I6 when pressed upwardly against the lower surface of strip 1 is loosely mounted on rod In and is supported in bellows 9 by a coil spring [8 positioned between disc I! and the bottom of said bellows.

At the top end of housing member 2, a valve member I9 is mounted. Valve member I9 comprises a main body portion 20 having a threaded lower shank 22 which isinserted through .an opening in the top of housing member 2 and secured thereto by a nut member 2| appropriate gaskets being employed to form an air-tight joint. Body portion 20 is provided with a hollowbore 23 communicating with the interior of housing member 2 and formed at its upper end with an orifice 24 communicating with an air-inlet port 25. A needle valve member 26 is threadedly engaged with the top wall of body portion 20 and extends axially downward with its tapered lower portion adapted to adjustably seat in orifice 24. The top of needle valve 26 is provided with a gear member 21 engaged by a worm element 28 formed on a horizontal shaft 29. Horizontal shaft 29 carries a knob 30 at its outer end provided with a pointer 3| adapted to be positioned opposite calibration values on a time scale provided on the outer surface of a main housing wall 31 adjacent said knob 30.

A bracket 32 of resilient metal or similar material is secured to the wall of body portion 20 by a screw 33 at an intermediate portion of said bracket. The upper end of bracket 32 carries an appropriate bearing support 48 for shaft 29 which maintains the alignment of shaft 29 so that worm 28' is constantly held in mesh with gear 21.

The lower end of bracket 32 is offset to form a I spring arm and carries a conical valve member 34 which is normally positioned in a tapered orifice 35 of substantial area provided in the side wall of body portion 20 and is normally maintained closed by the spring pressure of resilient bracket 32. A pull rod 36 is secured to the lower end of bracket 32 and extends through the main housing wall 31, being provided externally of said wall with an appropriate knob 38. By pulling on knob 38, valve member 34 may be unseated from orifice 35 to open valve l'9.

Mounted on support member is a bracket 39 on which is pivotally supported a bent lever 40 provided with a first actuator arm 4| extending laterally and adapted to bear upwardly on the bottom of bellows 9, and a second arm 42 slidably engaged with a pull rod 43 mounted for horizontal movement in support member Pull rod 43 extends through an opening provided in said second arm 42 and is appropriately headed beyond said opening to provide positive engagement with said second arm in a pulling direction. The external portion of pull rod 43 is provided with a knob element 44 having a thickened shank 45, transversely grooved at the bottom portion thereof to be normally engaged with a transverse lug 46 provided on a projection 41 secured to support member The grooved locking structure normally maintains pull rod 43 in the normal opencircuit position shown in Figure 1.

When it is desired to close a circuit connected to terminals 3 and 4, pull rod knob 44 is pulled out. This causes actuator arm 4| to push upwardly on the bottom of bellows 9 and urges disc ll into contact with contact elements l5 and I6, thus closing the circuit. The same action forces air out of housing 2 through orifice 35 of valve I9 against the spring pressure of resilient bracket 32. The circuit may be maintained closed, if so desired, by engaging the end of thickened shank 45 over transverse lug 46, there being sufficient looseness of fit between pull rod 43 and the opening provided therefor in support member to allow for the necessary upward inclination of the knob end of pull rod 43,

When the circuit is to be opened pull rod knob 44 is released, whereby the bottom of bellows 9 is likewise released from the upward mechanical pressure of actuator arm 4|. However, bellows 9 will not resume. its normal shape until enough air has entered housing member 2 through orifice 24 to substantially restore atmospheric pressure within bellows 9. The length of time required will be determined by the adjustment of needle valve member 26, as indicated by the calibrated scale value opposite the setting of pointer 3| on knob 30, the scale value being indicated in minutes or seconds.

When bellows 9 resumes its normal shape, disc I! drops out of contact with contact elements I5 and I6, thus opening the circuit.

Should it be desired to open the circuit at any time during the delay period, or without time delay after release of pull rod 43, knob 38 is pulled, unseating valve member 34 from orifice 35, thereby allowing air to quickly enter housing member 2 and bellows 9, thus allowing bellows 9 to quickly resume its normal shape.

While the foregoing structure provides a time delay for opening a circuit, a similar time delay may be provided for closing a circuit by changing the positions of the contact elements and the contact disc. Thus, the contact elements may be located in the top surface of strip 1, and contact disc I? may be mounted on rod l0, above strip 1, so as to normally rest on the contact elements but to be lifted out of contact with said contact elements until bellows 9 can resume its normal shape by the entry of air through the controlled orifice 24.

While certain specific embodiments of a time delay switch have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention will occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention other than as defined by the scope of the appended claims.

What is claimed is:

l. A time delay switch comprising a rigid housing member and a compressible bellows member connected to said rigid housing member to form a substantially closed chamber, a first terminal mounted on said housing member and electrically connected to a first contact element within said chamber, a second terminal mounted on said housing and electrically connected to a second contact element within said chamber, a bridging element carried by said bellows member within said chamber adapted to electrically connect said first contact element to said second contact element responsive to compression of said bellows member, a check valve mounted on said housing member formed and arranged to discharge air from said chamber when said bellows element is compressed but to normally prevent the entry of air into said chamber, and an adjustable orifice in said housing member adapted to allow the entry of air into said chamber at a restricted rate, said bridging member being adapted to move away from electrically connecting position with respect to said contact elements responsive to the restoration of normal atmos pheric pressure within said chamber.

2. A time. delay switch comprising a rigid bellshaped housing member and a compressible bellows member connected to the mouth of said housing member to form a substantially closed chamber, a first terminal mounted on said housing member and electrically connected to a first contact element supported within said chamber, a second terminal mounted on said housing member and electrically connected to a second contact element supported within said chamber, a metal disc member carried by said bellows member within said chamber formed and arranged to be moved into bridging relationship to said first and second contact elements responsive to compression of said bellows member, external means for at times compressing said bellows member, a check valve mounted on said housing member formed and arranged to discharge air from said chamber responsive to compression of said bellows member but normally preventing the entry of air into said chamber, and an adjustable orifice in said housing member adapted to allow the entry of air into said chamber at a predetermined restricted rate, said metal disc member being adapted to move out of bridging relationship to said contact elements responsive to the restoration of normal atmospheric pressure within said chamber.

3. The structure of claim 2, and wherein said metal disc member is slidably mounted on a rod secured to the compression wall of said bellows member and wherein a coiled spring is positioned around said rod between said metal disc member and said compression wall to normally support said metal disc member in spaced rela' tion to said compression wall.

DAVID B. JONES. 

